Jim Ladd, Free-Form Radio Trailblazer, Is Dead at 75

Even as FM rock stations moved toward more rigid playlists in the 1980s, Mr. Ladd fought to maintain his independence, in both music and message, often running afoul of station management. With his outspoken ways, he was said to be an inspiration for the 2002 Tom Petty song “The Last DJ,” an indictment of commercial radio that featured lyrics like “Well, the top brass don’t like him talking so much/And he won’t play what they say to play.”

In the liner notes for the album of the same name, Mr. Petty thanked Mr. Ladd for “his inspiration and courage.” “Let’s say it may have been partially inspired by me,” Mr. Ladd said in a 2015 video interview.

“I don’t want to say it’s about me,” he added, “but I am very, very honored, obviously.”

Mr. Ladd made stops at multiple stations over the years. In 2011 he joined SiriusXM satellite radio, where he was a host on the Deep Tracks channel. He remained there until his death.

In addition to his wife, Mr. Ladd is survived by a brother, Jon, and a sister, Veronna Ladd.

In a 2000 interview with The Los Angeles Times, when Mr. Ladd was back at KLOS, he broke out a handful of papers: the station’s playlist schedule, which mapped out the songs to be played over the course of the day — until his slot at 10 p.m., which remained blank. As in the old days, he could play what he chose. The only thing listeners could count on was Mr. Ladd serving up his trademark catchphrase, “Lord have mercy.”

When asked why he was allowed to follow his own muse when other D.J.s at the station were not, Mr. Ladd responded, “Stubbornness, stupidity, doggedness.”

The station’s program director, Rita Wilde, quoted in the article, offered a different take: “Not that many people, if you gave them the freedom, would know what to do with it.”